Allow for more explicit button labels

Allow for more explicit button labels

This commit allows us to very explicitly refer to any set of items
in text. This way buttons don't need to be labeled generically
like "Permanently Delete" but can be enriched to be labeled
"Permanently Delete "FileName"" or "Copy 7 Selected Folders" or
"Copy 6 Files" or "Rename "file1", "file2", "file3", "file4" and
"folder5"".

This commit tries to save translators a lot of work by using a
translation puzzle. This might be problematic for some languages.
The alternative on the other hand would mean that any label which
wants to be explicit would need to have over 10 translations just
for one label which seems quite bad as well.

A fallback is to be implemented for languages that can't really
accommodate for any specific word puzzle. This is explained in the
documentation.